The use of zinc oxide in rubber vulcanization is essential as it plays an important role in activating the vulcanization reaction by its role as an intermediate in the reactions of the accelerators, sulphur and the rubber. Also, zinc oxide increases the modulus of the rubber and acts a heat sink allowing better ageing properties of the rubber. The amount of zinc oxide used in rubber vulcanization is essentially in the range of 2 to 5 parts per hundred of rubber by mass. Considering the toxicity of zinc oxide to aquatic systems and current environmental considerations, it has become desirous to limit the amount of zinc oxide used in rubber vulcanization or replace it altogether.
It is an object of the invention to reduce the amount of zinc oxide in the vulcanization of rubber.